Conventionally, disposable products (for example, paper cups, disposable diapers, plastic bags, paper lunch boxes, or the like) have been manufactured and used by companies and service companies in various ways. However, such disposable products are mainly made of synthetic plastic as a raw material, and, thus, a disposal process after use thereof has caused a lot of problems such as environmental pollution and the like.
In order to solve such problems, a biodegradable substance (for example, polylactic acid (PLA)) which is biodegradable after use has been developed using a natural material such as corn starch. However, it takes a lot of cost to manufacture such a biodegradable substance. Therefore, such a biodegradable substance is not suitable for industrial mass production, and, thus, it has been limited in application but has not been widely used.
Thus, there has been a demand for alternative substances having a biodegradable property and also excellent in waterproofing property and strength for a certain period of time.